Broadband CDMA systems, in the near future, will provide a wide range of multi-media services including voice, data, and video. With multi-media traffic, users present the network with a range of bandwidth and quality of services (QoS) requirements.
The performance of a CDMA system is interference limited. Interference can cause disruption in the service of dedicated bandwidth or circuit data users who have been admitted into the system and guaranteed frame error rate and throughput targets. In order to provide the quality of service (“QoS”) guaranteed to data users, the interference in the system must be tightly controlled. Multi-access interference can be regulated by controlling the transmit powers of the users. Power control techniques that are designed only to combat fading, suffer the problem that an active new user can cause the signal to noise ratios of operational users to drop below their required threshold. Therefore, power control techniques must be designed to adjust the power when new users are admitted to the system, to maintain their guaranteed quality of service and for active link quality protection.
A detailed mathematical analysis of the affect of transmit power on the interference margin in a communications channel and how the link protection algorithm of the present invention was derived is presented in the following references, which are hereby incorporated by reference in their entirety:    D. V. Ayyagari and A. Ephremides in Power Control for Link Quality Protection in Cellular DS-CDMA Networks with Integrated (Packet and Circuit) Services. MOBICON 99 (Conference) Sep. 15, 1999.    D. V. Ayyagari, Capacity and Admission Control in Multi-Media DS-CDMA Wireless Networks. Ph.D. Dissertation, University of Maryland, College Park, 1998.